This invention relates generally to a heat sealer apparatus, and more particularly to such an apparatus for the localized heating of hot melt adhesive between folded superimposed plies of a continuous business form.
In preparation of certain constructions of business forms, such as confidential checks or media acceptable for mail processing, it has been the general industry practice to handle this as a two or three step process involving collating and envelope inserting. Previous attempts in preparing this product in one step following computer printout of the continuous web using adhesives around the inside face perimeter of a plow-folded web have met with only limited success due to the adhesive application difficulties or, with heat activated types of adhesives, due to the high thermal input necessary to raise the entire web and adhesive temperature to effect sealing, and the resultant web distortions initiated thereupon as a result of this high energy input, due to moisture imbalance created between the web and ambient air, in addition to general difficulties attendant to processing the web through a heating tunnel platen.